I, too, am searching for a flip case for my new Curve. I had a wonderful Bellagio case for my 7290, but haven't been able to find something comparable for the Curve.
1. All ports accessible
2. No bar or any other material across the face of the phone (I just got a beyza case with the material across the middle thinking I could work with it, but I can't - so to answer the OPs question, yes, that leather strip across the middle really really bothers me, using the trackball becomes very uncomfortable)
3. Pocket for credit card
4. Edge of case to actually come out slightly further than the phone, so that when I drop it, it is less likely to do any real damage
This is the one I had for the 7290: Leather pda case for your BlackBerry 6200 / 7200 / 7250 / 7290 Series Wireless Handheld
This is the one I am considering for the Curve: Piel Frama cases
I just hate that it is so pricey but I can't actually *hold* it before I put money out for it :(